The present invention relates to a lighting control system, and more particularly, to such a system specifically adapted for use with pinball games.
Typically, pinball game lighting is used to illuminate the playfield to allow the game player to clearly see the action on the playfield. Lighting is also used to highlight the backbox art to attract players to the game. Lighting has been used to accentuate the operation of playfield features and produce interesting visual effects. As pinball games have become more complex, improved microprocessor control of game lighting has become desirable.
It is well known in the art to employ microprocessors to control strings of bulbs connected in parallel. A microprocessor is used to turn on driver transistors to energize the lighting strings. However, this requires high power consumption and allows only simple "on-off" control of lighting strings. A more flexible means of controlling game lighting is desirable.
An improved method of lighting control employs triacs to energize lighting strings. Such a method is described in, for example, U.S. Pat. No. 3,941,926 to Slobodzian and U.S. Pat. No. 3,961,365 to Payne. These patents disclose a triac-controlled lighting system for use in energizing lighting elements on a large display system. The use of triacs reduces the power consumption. Triacs also allow enhanced controlled of lighting intensity because they can be used to supply the lighting strings with a.c. operating voltages. A zero crossing detect circuit may be used to signal the microprocessor when the a.c. voltage level crosses zero volts. The microprocessor can control the lighting intensity by delaying the firing of the triacs in relationship to the phase of the a.c. voltage. This technique is known as phase angle firing.
Although triac systems allow greater control, existing systems still fail to provide maximum flexibility in game lighting. A lighting system capable of monitoring playfield activity and adjusting the game lighting to achieve maximum player appeal while optimizing power consumption is desirable.
Accordingly, it is an object of the invention to provide a lighting control system for pinball games capable of independently adjusting the intensity of a plurality of lighting strings.
It is a further object of the invention to provide such a system having the capability of monitoring playfield conditions and adjusting the intensity of game lighting in response thereto.
It is another object of the invention to provide such a system which maximizes the useful life of lamps used in conjunction therewith.
These objects, as well as others, will become apparent to those skilled in the art from the detailed description of the invention provided below.